A Berkshire Hathaway investment in a Sudanese oil company is posing thorny problems for the Gates Foundation, the Los Angeles Times reports. Warren Buffet's investment outfit is the largest independent shareholder in PetroChina, whose parent company the U.N. and U.S. say funds Sudan's janjaweed militia—a stark contrast to the foundation's mission.
Buffett's $31 billion gift last year has drawn him into the controversy over how the Gates Foundation—which itself has smaller stakes in several Sudan-based oil firms—invests the money it later donates. The situation has increased attention on "St. Warren," long seen as a moral leader in the investment industry; he is also a trustee of the Gates Foundation. (Read more Warren Buffett stories.)